As the volume of fibers deployed into en-terprise increases significantly, fiber ca-bling advances like multifiber (MPO) con-nectors and interfaces between simplex,duplex and MPOs have evolved to reducespace and speed installations. The impor-tance of proper testing to effectively qual-ify and troubleshoot these more-com-plex links has also increased due tohigher data rates in both singlemode andmultimode fiber environments.

These more-stringent requirements
create challenges to simplify testing for
technicians, while also increasing testing efficiency and accuracy. Multimode
deployments are even more challenging
than singlemode due to the higher test
inaccuracies that occur due to optical
launch conditions (proper filling of the
fiber core during testing).

As network speeds continue to increase, so does the importance of ensuring pristine endface conditions. While
inspection is not specifically covered in
this article, proper implementation of
inspection and cleaning techniques for
all connector endfaces plays an equally
important role and is a prerequisite for
successful execution of all topics discussed herein.

Test improvement challenges

Today’s most significant test challengesfor Tier 2 in enterprise and data cen-ter fiber deployments can be summa-rized as follows: assessing multimode fi-ber links accurately; reducing test timefor multifiber connectors; enabling Tier2 testing by technicians of any skill level;facilitating effective troubleshooting ofMPO breakout cassettes. Let’s look ateach of these challenges in more detail.Accurate assessment of multimode fi-ber links—Incremental improvementshave been achieved over the years, butthis challenge has been ongoing sincethe beginning of multimode deploy-ments in the early 1980s. The chal-lenge is based on the fact that achiev-ing proper multimode fill conditions hasalways been difficult. Proper fill condi-tions refer to the transmitted light fullyfilling, but not overfilling the fiber core.Testing fibers with underfilled launchconditions understates loss values, whileoverfill conditions overstate losses.

Since 2012 encircled flux (EF) has
been implemented as a more-accurate